array_operations.rb

def array_stats(input_array)

  sum = input_array.inject(0) { |total, i| total + i }

  mean = sum / input_array.length

  def calculate_median(array)
    array = array.sort

    if array.length.odd?
      array[(array.length - 1) / 2]
    else array.length.even?
      (array[array.length / 2] + array[array.length / 2 - 1]) / 2.to_f
    end
  end

  median = calculate_median(input_array)

  return sum, mean, median
end

stats = array_stats([500, 12, 1, 99, 55, 12, 12])
sum, mean, median = array_stats([500, 12, 1, 99, 55, 12, 12])

puts sum
puts median
puts mean